The following invention relates generally to a method and apparatus for forming bags, preferably out of thermoplastic, films or laminates, but not limited to plastics, and the resultant article formed thereby.
More specifically, the invention embraces an instrumentality for forming bags which when fabricated include a pocket within which articles to be stored are disposed, the pocket including a turned down flap on a leading edge of the opening tacked into place on a surface of the bag. This doubled over portion allows a conventional purchase area to effect expeditious and facile opening of the bag and a corresponding area on another surface of the bag not folded over forms a lip type structure which can selectively occlude the opening.
There are bags commercially available which include a folded over portion or flap and an associated lip adapted to close an interior portion of the bag. These bags, commonly marked under the name Baggies.TM. are currently being manufactured with the opening of the bag parallel to the direction of travel of indeterminate length sheets of plastic materials. Thus, these bags are sold in containers that form stacks of the baggies and do not lend themselves to ready disposition and storage on a roll where they can be dispensed one at a time. The essential problem confronted in making bags of this type is the face that the slit which defines the opening allowing access to the interior of the bag, since it is coextensive with the width of the bag, does not allow sufficient purchase area of the bag by machinery for an endless web or sheet of indeterminate length to be drawn through processing stations and thereafter wound on a spool for subsequent dispensing. Thus conventional Baggies.TM. are stacked and not found on a spool.
Other types of bags are commercially known which are formed from tubular stock sealed at one end and allowed to remain open at the other end and perforations provided at both ends, the entire series of bags disposed on a roll so that they can be dispensed by tearing one at a time. Alternatively, rather than tubular stock, the bags of this nature can also be formed from sealing two sheets of material together along the edges. These types of bags are characterized as being extremely difficult to separate the two plys to gain access to the interior, and further no flap and associated lip is provided therewith for folding over the lip with respect to the flap so as to reliably contain that which is disposed within the interior of the bag. These bags are sealed with a twist tie or taped shut, heat sealed, glued, stapled or sewn.
Various other prior art attempts at providing an enclosure which serves the needs of society while lending themselves to mass production techniques are reflected in the following list of patents:
______________________________________ Patent Number Inventor Issue Date ______________________________________ 2,146,308 Maxfield Feb. 7, 1939 2,562,389 Piazze July 31, 1951 2,643,049 Bartelt June 23, 1953 2,921,731 Volckening, et al. Jan. 19, 1960 2,929,180 Abrams, et al. March 22, 1960 3,105,417 Hammer Oct. 1, 1963 3,117,712 Kugler Jan. 14, 1964 3,151,354 Boggs Oct. 6, 1964 3,254,828 Lerner June 7, 1966 3,469,769 Guenther Sept. 30, 1969 3,979,050 Cilia Sept. 7, 1976 4,344,557 Lerner Aug. 17, 1982 4,401,213 Lerner Aug. 30, 1983 ______________________________________
The patents to Lerner '828 is interesting since he teaches the use of flexible container strips in which first and second plys are intermittently sealed and one of the plys is provided with an elongate slit transverse to the direction of sheet fabrication travel and a plurality of perforations provided allow dissociation of adjacent containers formed thereby. Appropriate air jets are utilized to separate the two plys to allow admission of articles within the thus formed enclosure. A cursory analysis of this teaching makes it manifest that no planar lip of comparable configuration to that which is disclosed in the instant application is to be found, and therefore the resultant structure does not lend itself to the type of utilization which has made Baggies.TM. so popular. Moreover, this citation is silent on the means by which the ply having an opening slit that extends the entire width of the thus formed bag is advanced before the sheets are joined together. That is to say, the slits formed as the opening preclude the advancement of that ply of material downstream due to the discontinuous nature of that ply.
The remaining citations which show the state of the art further diverge from that which is defined as the nexus of the invention continued in the ensuing claims.
With greater specificity, however, the instant application is distinguished over the known prior art in that an apparatus, method therefor and resultant articles have been disclosed which allow for the formation of a plurality of bags embodied as a linear series, each of the thus formed bags defining enclosures having openings which by virtue of the construction technique are capable of extending the entire width of the bag transverse to the direction of travel of the series, the series of bags connected in end-to-end relationship with the bottom and top of bag forming the areas of adjoinment with adjacent bags, so that the bags when formed can be stored on a roll. The bags themselves include a turned over flap portion on a one ply which is adapted to communicate with a lip formed from another ply of the bag. Optionally, the bag may include during its formative steps a pleat or gusset, and one embodiment orients the reinforcing flap which was adjacent the opening and places it at the bottom of the bag to provide reinforcement at the bottom. The apparatus and method also lend itself to forming a bag having first and second separate interiors formed from sealing edges together three plys of material so that an axis of symmetry is provided by the medial ply. Optional slots fo facilitate carrying the tote bag are also incorporated on all three sheets.
To effect formation of the bags, an apparatus and method for manipulation of the apparatus includes providing at least two rolls of sheet material, forming flaps in one of the sheets by cutting a three sided flap, tacking the thus formed flaps against the same ply of sheet material, sealing the two plys of material along side edges thereof so that an enclosure is formed, optionally forming gussets along side panels of the bag, and end sealing adjacent bags including providing perforations to allow disassociation of adjacent bags. When a dual enclosure system is provided, a third roll of sheet material is provided which enjoys the flap forming and flap tacking steps, the roll provided without flaps serves as the medial substrate between the two flap including sheets, which are all thereafter cojoined along outboard edges. In a preferred form of the invention, the width sheet material is a whole number multiple N of a single bag's width so that if the width of the bag is W, and the width of the sheet material is NW, N rolls are formed at the output station by providing a final serving step between adjacent bags widthwise, to benefit from the economies of scale in an extra wide operation. More importantly, the flaps formed are staggered with respect to laterally adjacent bags that are being formed so that a serpentine continuous path of sheet material exists providing a tractive surface allowing advancement of the sheet goods even though the slit defining the opening of the bag is substantially the width of the finished bag. That is, there is a continuum of material that weaves around the tacked back flaps in a serpentine fashion so that there is sufficient sheet material to drivingly support bags having openings the width of which is substantially equivalent to the width of the bag.
Optional flaps may be cut out and removed completely, or left untacked.